1. Field of the Invention
The invention is directed to an arrangement for fastening a flexible printing plate on a form cylinder of a printing press, which form cylinder has at least one axially extending cylinder cavity that supports a leading leg of the printing plate at an edge formed by a first wall of the cavity which terminates at all acute angle with the outer surface of the cylinder. The trailing leg of the printing plate contracts a second, approximately radial wall of the cavity. A plurality of plate-like springs are provided along the length of the printing plate to press the leading and trailing plate legs against the appropriate cavity wall.
2. Discussion of the Prior Art
In EP Application 93 11 233 1.9, the clamping of plates is effected in that the legs of the printing plate are inserted in slots in the form cylinder. A plurality of plate-like springs are located in the slots to secure the plate legs by pressing the latter against the walls of the slot. However, the springs impede removal of the plate, particularly an automated removal.
In DE-AS 27 44 371, plate legs which are inserted into the cylinder cavity are pressed and secured against cavity walls by springs. The springs can be pulled away from the plate legs in order to remove the plate. For this purpose, knobs are displaced using costly mechanisms and a key must be inserted into the clamping groove to actuate the mechanisms. Aside from the extra expenditure involved in design and operation, the device also requires a wide clamping groove.
In EP 0 534 579 A2, a swivelable spindle is located in the cylinder cavity of a plate cylinder. The spindle has a plurality of U-shaped leaf springs which are distributed along the length of the spindle in a groove. In cooperation with a wall of the cavity, one side of each leaf spring clamps the forward or leading leg of the plate. The rear or trailing leg of the plate is secured in the other side of the leaf spring which is beveled. For this reason, the trailing plate leg itself must also be provided with an additional right-angled bevel. This additional beveling adds to the cost of the plate bending machine and also requires a wider clamping groove. Furthermore, the materials from which the printing plate is made have low mechanical strength so that there is a risk that the clamping forces of the printing plate will bend the right-angled bevel of the printing plate and cause the printing plate to detach. Finally, the clamping device works with three operating positions of the spindle. Two different positions of the plate cylinder, necessitating suitable control and position-reporting devices, are required to realize these positions.